The Effect of a Magnetic Field on Ion-Exchange Selectivity and Capacity

Two chemical free/semi free technologies that have been used for treatment of ionic water streams are magnetic field and ion exchange. While ion exchange technology is well understood, the scientific debate on the role and impact of a magnetic field on an ionic environment is ongoing. The objective of this preliminary study was to examine the synergistic effects of a magnetic field on the selectivity and capacity of two ion exchange materials, one ferromagnetic (HISORB) and the other non-ferromagnetic (Purolite C-104). Initial column runs using an iron based ion-exchange material, HISORB, have shown a significant difference in breakthrough times of specific ions when comparing column runs done in the presence of a magnetic field to one without (control column). In particular, a set of column runs were tested for solutions containing five transition metals: lead (II), nickel (II), cadmium (II), copper (II) and zinc (II), each at a concentration of 0.05 mM. The influent pH was maintained at about 5.5 for both columns and the hydrodynamic conditions were identical. The data from the column runs with the magnetic field showed Ni²⁺ and Cd²⁺ breaking through at almost 500 bed volumes (BV) earlier than the Ni²⁺ and Cd²⁺ in the control column while the breakthrough time of the remaining three metals, Cu²⁺, Pb²⁺, and Zn²⁺ stayed about the same. In contrast, column runs using an organic based ion-exchanger, Purolite C-104, in the presence of a magnetic field proved to have only minor impact on break through times of ions when compared to the control column runs.